67 - a civilian motorbike/car/truck in working condition, the engine is still running, it's as if it was hurriedly abandoned minutes earlier.
68 - a circle of dead dogs, laid nose to tail (I actually encountered this in an online game, no explanation was ever given for the circle, it was just one of those weird things you encountered and were left to wonder about).

These are all meant to be scenes to make the Players wonder. They have no answer to their mystery and they have no connection to the adventure unless of course you choose to incorporate them into your scenario.

A macabre scene of two recently dead enemy soldiers in a shellhole, arranged as though they are playing poker for empty bottles of booze (the bottles have traces of alcohol in them and they still smell of some rotgut whisky). The bodies are propped up with sticks. Their uniforms are dirty and torn and they have no usable equipment except the pack of cards.

A collection (2d10+2) of boots. They're in a range of sizes and all in usable condition except that they are all for the left foot (or the right foot, if you will).

A NATO Kevlar helmet with scraps of hair and large splotches of blood. Nothing particularly unusual except that the helmet has been cut into two halves and what you're looking at is the right side half.

A crashed military light truck/jeep. There's bloodstains on the seats but the most interesting thing is that there are several circular saw blades embedded deep into the bodywork, doors and the windscreen. It's as though they were launched from some device. Some of them have penetrated through the doors and could have injured the person sitting next to that door.
(If you want to give the Players a clue, I imagined this scenario as one where the attackers had built themselves a ballista or three that could fire the sawblades. One ballista may have been damaged and left behind and can be found nearby in a typical ambush position, with about a dozen unused sawblades piled next to it).

EDIT: I meant to say as well, that these are in response to Draq's request for some more of the "stranger" things to encounter.

These are all meant to be scenes to make the Players wonder. They have no answer to their mystery and they have no connection to the adventure unless of course you choose to incorporate them into your scenario.

A macabre scene of two recently dead enemy soldiers in a shellhole, arranged as though they are playing poker for empty bottles of booze (the bottles have traces of alcohol in them and they still smell of some rotgut whisky). The bodies are propped up with sticks. Their uniforms are dirty and torn and they have no usable equipment except the pack of cards.

A collection (2d10+2) of boots. They're in a range of sizes and all in usable condition except that they are all for the left foot (or the right foot, if you will).

A NATO Kevlar helmet with scraps of hair and large splotches of blood. Nothing particularly unusual except that the helmet has been cut into two halves and what you're looking at is the right side half.

A crashed military light truck/jeep. There's bloodstains on the seats but the most interesting thing is that there are several circular saw blades embedded deep into the bodywork, doors and the windscreen. It's as though they were launched from some device. Some of them have penetrated through the doors and could have injured the person sitting next to that door.
(If you want to give the Players a clue, I imagined this scenario as one where the attackers had built themselves a ballista or three that could fire the sawblades. One ballista may have been damaged and left behind and can be found nearby in a typical ambush position, with about a dozen unused sawblades piled next to it).

EDIT: I meant to say as well, that these are in response to Draq's request for some more of the "stranger" things to encounter.

Ooh yes thank you. You come across these kind of unexplained things in video games if you look around enough and I find it adds a pleasant mix of fear, confusion and curiosity

1. Not a weird encounter but something a little unusual.
When the PCs investigate, the find a small collection of "drip" rifles (AKA "pop-off" rifles or more aptly, the "ghost" or "phantom" rifle) in various defensive positions.
The rifles can be any sort from combat to civilian rifles and may be set to fire single or auto (the small number of ejected shells from self loading rifles indicates that the bursts where small, 3-5 rounds only).

The "drip" rifle is a device that allows the rifle to self-fire. First used by Australian forces during the evacuation from Gallipoli, it consists of the rifle and a pair of tins (or any suitable collection device like canteen mugs etc. etc.) arranged one above the other. The rifle is typically held in place by sandbags or a wooden frame.
The lower tin has a line connected to the trigger and the upper tin has sand or water that has been allowed to drip into the lower tin.
When the lower tin gained enough weight, it would pull the trigger and thus give the impression that someone was still in the trench taking shots at the enemy.

2. And another that is slightly weird, that I recall from somewhere (a movie I think)...

A small stand of trees survives unscathed by the battle. When the PCs approach the trees the only notable thing is a breeze blowing through the area... and the noise.
There's a weird, sort of moaning, sound coming from the direction of the trees. It sounds like something you would encounter in a horror movie. There's no melody or rhythym to the noise other than the "moaning" quality.

When (or if) the PCs investigate they find that someone has placed several lengths and sizes of PVC pipe in the trees. They have cut them and arranged them like a giant set of pan pipes and placed them into position so that they will catch the wind and emit the strange sound the PCs heard.

Someone has spent a great deal of time collecting and hanging dogtags from a tree on the battlefield. There are so many dogtags that it's doubtful they are from soldiers killed on this particular battlefield. There are so many of them that when the wind blows, the dogtags act like a windchime.

For some variety and to increase the weirdness factor, instead of dogtags (which are somewhat understandable, perhaps the person was creating a memorial for example), someone has tied chess pieces to the branches of the tree. There are hundreds of them made from plastic, wood and even metal or stone but they are all pieces used in chess.
Of course you could just go into "creepy" territory and have the tree festoned with dolls or stick figures (like in the first Blair Witch movie).

An alternative is to throw all you're ruined/non standard ammo on a fire with alot of leaves/green branches. Creates a thick smoke and a timed 'simulation' of gunfire. Used for distractions/diversions.

1. An old leather shoulder bag - an officer's case from a previous generation - no one makes these things of leather for field use any more. It's heavy if you pick it up.

It contains a 1 kg. bar of gold, stamped with an eagle over a swastika, and a (random) 8-digit number.

2. A set of 8-12 test tubes on stands on the ground. Some have dried out stuff in different colors in them.

Uncle Ted

Nice!
I really like these because of that "What the... ?" factor, particularly the test tubes. There's nothing quite like something completely random but hinting of danger, to make the players paranoid!

A baby and/or small child
A kitten or puppy
A bag of silver coins
A women who has been held as a slave
A box of fine china (looted from a house)
Unexploded 500 lb bomb
RPG round that was fired with the nose fuse cover on
A historic weapon of some time (matchlock musket for example)